There’s a hypothetical that I find difficult to answer from a socialist perspective, which is “The factory factory” - as in, a factory that produces factories, or a MoP that is used to produce other MoP’s. If I work in a factory producing machinery which someone else uses to make a product, then am I entitled to compensation? If no, then it seems like I haven’t been compensated for my labor which is a problem, but if yes then that seems like we’re right back to capitalism.

Any form of socialism that doesn't abolish markets should be able to deal with this, as you're still just selling goods at the end of the line then.